Method of controlling a device allowing a user to walk or run on the spot in an arbitrary direction and device therefor

ABSTRACT

The invention concerns a method for controlling a device ( 1 ) allowing a user ( 25 ) to walk or run on the spot in an arbitrary direction and a device ( 1 ) therefor. The device ( 1 ) comprises a stationary central platform ( 9 ) surrounded by a convex polygon shaped deck ( 6 ) in level therewith, said deck ( 6 ) being divided into trapezoid shaped roller conveyors. Each conveyor has rollers in parallel with the trapezoid bases, the shorter one of these adjoining said platform and the longer one of these forming a side of said polygonal shape. The rollers of said conveyors are driven in order to move a user ( 25 ) stepping thereon back to said central platform ( 9 ). The rollers as such are continuous circular cylindrical, and beneath them there is a driving belt for frictional driving engagement with the rollers from below. According to the method a marker ( 26 ) placed on top of the user ( 25 ) is monitored by means of video cameras ( 24 ) and the speed of the roller conveyors adjusted depending on the perceived marker size and position.

TECHNICAL FIELD

The present invention concerns a method for controlling a deviceallowing a user to walk or run on the spot in an arbitrary direction,the device comprising a stationary central platform surrounded by aconvex polygon shaped deck in level therewith, said deck being dividedinto trapezoid shaped roller conveyors, wherein each conveyor hasrollers in parallel with the trapezoid bases, the shorter one of theseadjoining said platform and the longer one of these forming a side ofsaid polygonal shape, and wherein the rollers of said conveyors aredriven in order to move a user stepping thereon back to said centralplatform. Further, the present invention concerns a device controlled bysuch a method.

PRIOR ART

A device of the kind in question is previously known from theinternational application WO 96/35481 A2. In that application anembodiment of a device is revealed, comprising trapezoid rollerconveyors having rollers divided into two equally long circularcylindrical parts with a central waist part inbetween. Further revealedtherein is a method of controlling said device based upon data fromaccelerometers provided on the user of the device.

The known device and method raise several concerns about safety. For onething, the waist part of the rollers increases risk of a user's clothinggetting entangled in a hazardous way, even if said waist part, asindicated, is partly covered by means of a countersunk cover strip.Furthermore, the accelerometers used for the known method are hardly ofany use when it comes to detecting the user stumbling, which for safetyreasons would necessitate an immediate halt of the conveyors in order toavoid risk of squeezing for instance a finger.

Then the known device has some practical drawbacks, too. The mounting ofthe rollers is rendered quite complicated by the way chosen to drive therollers, regardsless if a belt is used, encompassing the rollers andthus hampering their mounting or dismounting, or cog wheels are used,necessitating use of intermediate gears in order to get neighboringrollers rotate in the same and not opposite directions.

Another prior art device is revealed in WO 2010/089618 A2. This devicealso comprises a platform made of trapezoidally shaped roller conveyors,but the rollers of these are of a safer design. They are continuouscircular cylindrical and are driven by friction wheels from below, whichminimises the risk of a user's clothing getting entangled. Forcontrolling the device and keeping the user in the middle of theplatform a circular railing is used, that encompasses the user at somedistance. The railing can carry sensor means measuring the distance ofthe user from the railing, wherein the distance data is used as an inputfor controlling the roller conveyors.

The latter device is far easier to assemble than the former one, but thegreat number of friction wheels used therein leaves some room forimprovement. Further, the use of distance measuring sensor meansarranged on a circumferential railing does not render it possible tocontrol the device safely for instance when a user kneels or stumblesand falls.

OBJECT OF THE INVENTION

Against that background a first object of the invention is to devise amethod of controlling a device according to the preamble in anadvantageous way. A second object of the invention is to provide adevice with improved trapezoid shaped roller conveyors.

SHORT SUMMARY OF THE INVENTION

According to the invention the first object is achieved by means of amethod according to the preamble further characterized by the followingsteps: mounting a plurality of video cameras above the device on aheight well above a user thereof, said cameras being arranged in adefined matrix and directed downwardly; providing a direction indicatingmarker on top of said user; monitoring the position and size of saidmarker by means of said cameras; controlling the speed of the rollerconveyors depending on said markers distance from said central platformas seen from above by said cameras at an elevated speed when saiddistance is large and at a lower speed when said distance is small; andhalting the roller conveyors when said distance is nil. By using videocameras instead of accelerometers, like in the prior art device, theuser only has to wear a simple marker, e.g. on top of a cap or helmet,to get connected to the device. Thus, there is no need of wiring orfitting battey packs or the like, which enhances both convenience andsafety. Further, by placing the marker on top of the user instead of onhis arm or legs, which are moving to and fro while walking or running,monitoring of the users actual position and adapting the roller conveyorspeed thereto becomes more safe and a lot easier.

The method according to the invention preferably comprises the furtherstep of halting the roller conveyors when the size of said marker asseen from above by said cameras is substantially decreased or when themarker can no longer be seen at all by said cameras. This step marksanother important safety feature, because it ensures that the rollerconveyors of the device according to the invention come to an immediatehalt should the user kneel or lie down or trip and fall or just lose themarker.

The method according to the invention preferably comprises the furthersteps of mounting video displays or screens, that can be viewed by theuser, and of adapting the content shown on said video displays orscreens to the speed of the roller conveyors, the actual position andsize of said marker and to its direction. This makes it possible togreatly enhance the users overall perception in a virtual realityenvironment created by means of said video displays or screens. Further,according to a preferred embodiment the theme to be shown on said videodisplays or screens can be chosen depending on the type of marker used.This makes the device according to the invention more user friendly andadaptable, for instance by simply changing from one cap, having one typeof marker thereon, to another cap, having another typ of marker thereon.

The method according to the invention preferably comprises the furtherstep of lowering the speed of the roller conveyors if the direction ofthe marker on top of the user indicates that the user, having stepped onthe deck is facing in a non-radial direction in relation to the centralplatform. This step takes into consideration that a user, who forexample turns his head while walking, usually slows his walking speedand therefor could become unbalanced if moved to fast by the rollerconveyors of the device according to the invention.

According to the invention the second object is achieved by means of adevice for allowing a user to walk or run on the spot in an arbitrarydirection, the device comprising a stationary central platformsurrounded by a convex polygon shaped deck in level therewith, said deckbeing divided into trapezoid shaped roller conveyors, wherein eachconveyor has rollers in parallel with the trapezoid bases, the shorterone of these adjoining said platform and the longer one of these forminga side of said polygonal shape, and wherein the rollers of saidconveyors are driven in order to move a user stepping thereon back tosaid central platform, wherein said rollers are continuous circularcylindrical, and wherein beneath each conveyor there is a driving meansfor frictional driving engagement with said rollers from below, saiddevice being characterized in that said driving means comprises anendless belt extenting along the roller conveyor in frictional drivingengagement with all rollers thereof, and in that said driving meansfrictionally engages the conveyor rollers in a central part of these,said rollers being journalled at end parts thereof in resilientlymounted bearings. Compared to WO 96/35481 A2 this facilitates not onlythe production and mounting of the trapezoid roller conveyors and theirrollers, but also service measures, because for example no driving beltshave to be dismantled in order to lift off a conveyor. Further thedevice according to the invention improves safety in that the rollerconveyor surfaces become smoother and less rugged than before, therebyreducing risk of clothing entanglement or finger sqeezing. Further,compared to WO 2010/089618 A2 a device according to the invention ismuch easier to accomplish than a drive solution comprising individualrubber wheels, and the built in resiliency of the device according tothe invention makes the roller conveyor more pleasant to walk or runupon, just like a slightly resilient sporting floor, and assures gooddriving contact between the rolls of a conveyor and said driving meanseven if a user steps on rolls far from the central parts of these.

Preferably the driving shafts of said driving means are interconnectedby flexible joints and driven by a single motor. It is well known to useflexible joints, also known as universal joints, to transmit arotational movement around a corner, if the angle of that corner iswithin reasonable limits. Thus, in the device according to the inventionone such joint may be used at every transition between two adjoiningroller conveyors in order to transmit power from a single motor to allof the conveyors in minor angular steps that do not cause any blockingproblems.

The deck of the device according to the invention is preferablycircumferentially enclosed by a stationary floor plate in leveltherewith. The floor plate marks the outer limits of the device and canbe used as a safety retreat, for example if the speed of the rollerconveyors of the device is to slow to carry the user back to the centralplatform.

Preferably said floor plate covers parts of said driving means. This isvery advantageous, because it simplyfies access to the driving means.Further, it makes it possible to minimise height of the device, becausefor example the preferred single motor, which has to be of considerablesize, thus can be hidden below the rather thin floor plate instead ofbelow a rather thick roller conveyor.

According to a preferred embodiment of the device according to theinvention said deck is of regular convex polygon shape and its rollerconveyors are of uniform isosceles trapezoid shape. A solution like thatis the most advantageous one if a device is to be created allowingwalking or running in arbitrary directions without any limits, whichcould be the case if the outer limits of some of the roller conveyorswere close to the central platform while others were not.

SHORT DESCRIPTION OF THE DRAWINGS

In the drawings a preferred embodiment of the device according to theinvention is shown and a preferred embodiment of the method according tothe invention illustrated, wherein:

FIG. 1 shows the preferred embodiment of the device according to theinvention in a perspective view;

FIG. 2 shows the device according to FIG. 1 from above;

FIG. 3 shows portion A of FIG. 2 in greater detail with some partsbroken away;

FIG. 4 shows the device in a side view along section B-B in FIG. 2;

FIG. 5 shows portion C of FIG. 4 in greater detail; and

FIG. 6 shows, in a perspective view, a user of the device, the deviceitself and other means needed to perform the method according to theinvention.

DESCRIPTION OF A PREFERRED EMBODIMENT

The device 1 according to the preferred embodiment of the invention isgenerally circular when seen from above. The circle periphery is createdby a horisontal ringshaped floor plate 2, which by radial lines isdivided into several sectors 3. In total there are sixteen identicalfloor sectors 3, all of them resting on a framing structure 4 includingradial beams 5 underneath the division lines. The framing structure 4with its radial beams 5 is best seen in FIG. 3, where two floor sectors3 are removed to reveal the substructure of the device 1. At the innercircumference of the ringshaped floor plate 2 each floor sector 3 formsa line, that runs straight from one of the division lines to the next.This makes the sixteen floor sectors 3 create a regular hexadecagonshaped ring opening.

Inside of the ring opening of the ring shaped floor plate 2 a horisontaldeck 6 is provided in level with the floor plate 2. The deck 6 too isring shaped and concentric with the floor plate 2. The deck 6 consistsof a total of sixteen identical roller conveyors 7, each one of anisosceles trapezoid shape with rollers 8 in parallel with the trapezoidbases. The sixteen roller conveyors 7 are radially aligned each with oneof the sixteen floor sectors 3 and connect to these without any majorinterruption each with a roller 8 along the longer baseline of theroller conveyor 7 in question. The opposite rollers 8 along the shorterbaselines of the roller conveyors 7 define a regular hexadecagon shapedopening, which forms the inner circumference of the deck 6.

Finally, inside of the ring opening of the ring shaped deck 6 ahorisontal central platform 9 is provided in level with both the floorplate 2 and the deck 6. The platform 9 is stationary and has the shapeof a regular hexadecagon and a size that fits the inner circumference ofthe deck 6 without leaving any major interruption. Like the floor plate2 the central platform 9 is resting on said framing structure 4, whichhas its radial beams 5 running all the way into the center of thecircular device 1.

The deck 6 is also resting on the framing structure 4, however notdirectly on the radial beams 5 but, as can be seen in the detailed viewin FIG. 5, on resilient elastomer strips 10 mounted on top of these. Onsaid strips 10 side boards 11 of the roller conveyors 7 rest. The sideboards 11 are kept in place by means of studs 12 which are attached tothe radial beams 5 and freely pass orrifices in said side boards 11,thus enabling some suspended side board movement within limits given byheads of the studs 12 protruding on top of said orrifices.

The rollers 8 of the roller conveyors 7 are journalled in bearings 13held by said side boards 11 and mounted as close as possible to eachother without touching each other both in parallel within one and thesame roller conveyor 7 as well as sideways between two roller conveyors7 adjoining on top of a radial beam 5 of said frame structure 4. Thus,the rollers 8 would be freely rotable if there was not a driving means14 arranged underneath them in frictional contact with each of them.

As can be seen in FIG. 3, according to the preferred embodiment of theinvention the driving means 14 for every roller conveyor 7 comprises anendless belt 15. The belt 15 extends radially towards the center of thedevice 1, centrally in relation to the roller conveyor 7 in question. Bymeans of a sliding support 16 under the upper course of each endlessbelt 15 these courses are pushed into frictional engagement with allrollers 8 of the roller conveyors 7, wherein the resilient suspension ofthe roller conveyors 7 ensures perfect belt-roller contact even insituations where the rollers 8 are loaded eccentrically.

Each one of the endless belts 15 runs about end pulleys 16, 17, of whichpreferably the inner one 16 is a idling pulley and the outer one 17 is adriving pulley. Further, the driving pulleys 17 are driven by means of acardan shaft arrangement 18, that comprises flexible joints 19 on bothsides of the driving pulleys 17 and runs from a single electric motor 20to a first driving pulley 17 and from there to the next driving pulley17, and so on.

As can be seen best in FIG. 3, the cardan shaft arrangement 18 is wellhidden below the floor plate 2 and yet easily accessible by simpleremovement of chosen floor sectors 3. The same goes for the rollerconveyors 7, which are fairly easy to remove thanks to the fact thatthey are frictionally driven and thus can be lifted off easily once thesecuring studs 12 are removed.

In FIG. 6 the device 1 according to the preferred embodiment describedabove is shown together with some extra features provided in order torender a method of controlling the device 1 possible. In FIG. 6 theprevious reference numbers are mostly omitted, because the perspectiveview of the device 1 as such is identical with the one in FIG. 1.

Besides device 1 the arrangement in FIG. 6 comprises a cage 21, thatsurrounds the device 1. The cage 21 has erect post 22 and a roofcomprising diagonally extending rails 23. The posts 22 are preferablyused to mount video displays or screens (not shown) that enable creationof a per se known virtual reality environment. The rails 23 carry videocameras 24, which are directed downwardly. As can be seen the videocameras 24 are arranged in a well defined matrix at a height well abovea user 25 of the device 1. The user wears a cap on top of which there isa marker 26 of a defined pattern that is direction indicating.

In the method according to the invention the video cameras 24 track theposition of the marker 26, the size thereof and its direction and usethat information in order to decide where the user 25 of the device 1presently is and where he is heading or facing. If the user is not inthe center of the device 1 on the stationary platform 9 or leaves theplatform 9, the electric motor 20 is activated in order to drive theroller conveyors 7 and make them return the user 25 stepping thereon tothe platform 9. According to the method the speed with which the user 25is returned to the stationary platform 9 is higher the further away theuser 25 is from the platform, which means too that speed is lowered oncethe user 25 comes close to or is close to the stationary platform 9.Once the user 25 is back on the stationary platform 9, the electricmotor 20 is again stopped and thus the roller conveyors 7 halted. In themethod according to the invention they are halted as well if the marker26 on top of the user 25 becomes obscured or no longer is detectable,which can be due to the user 25 stumbling and falling or stepping pastthe deck 6 and onto the floor plate 4, or due to the marker 26 comingoff for some reason. Further, a detected change of perceived size of themarker 26, which can be due to the user 25 kneeling or lying down, canbe used as an indicator to immediately stop the roller conveyors 7 forsafety reasons.

In a more advanced control mode based upon the method according to theinvention the speed of the roller conveyors 7 is based on the positionof the user 25 relative to the central platform 9 with theretooptionally derivating elements to account for the time over which userpositional changes occur and adapt the speed of the roller conveyors 7accordingly, and integrating elements to allow faster maximum conveyorspeeds over time.

The method according to the invention can comprise the further steps ofmounting video displays or screens (not shown), that can be viewed bythe user 25, and of adapting the content, that is the viewing angle orthe moving speed, of the content shown on said video displays or screensto the speed of the roller conveyors 7, the actual position and size ofsaid marker 26 and to its direction. Further, it is well possible tochose the theme to be shown on said video displays or screens independence on the type of marker 26 used, such as a marker 26 onmilitary helmet for initiating a combat scene or a marker 26 on astation-master cap for initiating a train platform scene.

Finally, the method according to the invention can further comprise thethe step of lowering the speed of the roller conveyors 7 if thedirection of the marker 26 on top of the user 25 indicates that the user25, having stepped on the deck 6 is facing in a non-radial direction inrelation to the central platform 9. This takes into consideration thefact that a user 25, who turns his head while walking, usually slows hiswalking speed and therefor could become unbalanced if moved to fast bythe roller conveyors 7 of the device 1 according to the invention.

1. A method of controlling a device allowing a user to walk or run on the spot in an arbitrary direction, the device comprising a stationary central platform surrounded by a convex polygon shaped deck in level therewith, said deck being divided into trapezoid shaped roller conveyors, wherein each conveyor has rollers in parallel with the trapezoid bases, the shorter one of these adjoining said platform and the longer one of these forming a side of said polygonal shape, and wherein the rollers of said conveyors are driven in order to move a user stepping thereon back to said central platform, wherein the method comprises the following steps: mounting a plurality of video cameras above the device on a height well above a user thereof, said cameras being arranged in a defined matrix and directed downwardly; providing a direction indicating marker on top of said user, monitoring the position and size of said marker by means of said cameras; controlling the speed of the roller conveyors depending on said marker's distance from said central platform as seen from above by said cameras at an elevated speed when said distance is large and at a lower speed when said distance is small; and halting the roller conveyors when said distance is nil.
 2. The method according to claim 1, further comprising the step of halting the roller conveyors when the size of said marker as seen from above by said cameras is substantially decreased or when the marker can no longer be seen at all by said cameras.
 3. The method according to claim 1, further comprising the steps of mounting video displays or screens, that can be viewed by the user, and of adapting the content shown on said video displays or screens to the speed of the roller conveyors, the actual position and size of said marker and to its direction.
 4. The method according to claim 3, further comprising the step of chosing the theme to be shown on said video displays or screens depending on the type of marker used.
 5. The method according to claim 1, further comprising the step of lowering the speed of the roller conveyors if the direction of the marker on top of the user indicates that the user, having stepped on the deck is facing in a non-radial direction in relation to the central platform.
 6. A device for allowing a user to walk or run on the spot in an arbitrary direction, the device comprising a stationary central platform surrounded by a convex polygon shaped deck in level therewith, said deck being divided into trapezoid shaped roller conveyors, wherein each conveyor has rollers in parallel with the trapezoid bases, the shorter one of these adjoining said platform and the longer one of these forming a side of said polygonal shape, and wherein the rollers of said conveyors are driven in order to move a user stepping thereon, back to said central platform, wherein said rollers are continuous circular cylindrical, and wherein beneath each conveyor there is a driving means for frictional driving engagement with said rollers from below, wherein said driving means comprises an endless belt extenting along the roller conveyor in frictional driving engagement with all rollers thereof, and that said driving means frictionally engages the conveyor rollers in a central part of these, said rollers being journalled at end parts thereof in resiliently mounted bearings.
 7. The device according to claim 6, in which driving shafts of said driving means are interconnected by flexible joints and driven by a single motor.
 8. The device according to claim 6, in which said deck is circumferentially enclosed by a stationary floor plate in level therewith.
 9. The device according to claim 8, in which said floor plate covers parts of said driving means.
 10. The devive according to claim 8, in which said deck is of regular convex polygon shape and its roller conveyors are of uniform isosceles trapezoid shape. 